It also works when I try to connect from the outside. Sounds wacky, but trust me. I actually got blocked from the server when using 68.36.233.177 after previously being connected because the ports were closed. lol

Also, you're probably going to need to do a /whitelist reload after adding someone. Try and make sure their name is all lowercase. I'm not entirely sure if it matters, but that's how the game handles it.